campbell



(No Model.) 3 Sheets-Sheet 1. A. CAMPBELL. AIR CUSHION POR THEREGIPROGATING BEDS OP PRINTING PRESSES.y

j wi NV E N .O R

Zy his Attorneys, M NA remis. Phawmmnpher. www n. c.

Patented Jem-11. 15, 1884.

IUI l l l l l l l l I l l l I l l l l l l l Il UUll Em FF WITNESSS:

3 sheets-sheet`2- A.. CAMPBELL.

Patented Jan. 15, 1884.

ENTOR:

INV

(No Model.)

AIR CUSHION FOR THE REGIPROCATING BEDS 0E PRINTING PRESSES. No. 291.875.

3 Sheets-Sheet 3.

(No Model.) A

A. C11M11? 11I |I...y AIR CUSHION FOR THE REUIPROUATING BEDS 0I'PRINTING PRESSES. No. 291,875. Patented Jan. 15, 1884.

i-mzpzm?. z -.m f//v//////////////////////Z i .5f/Z

n c m I ,i

WITNESSES:

Mrk

I N V E N TO R By his .f1 ttorneys, I

u4 FUCHS Phmhljlhngnpwr, Wnshmglon. ElV EA ilsiirn` Brei-ns Armar Fries.

ANDREV CAMPBELL, OF BROOKLYN, ASSIGNOR TO JOHN AND EDMUN) llllcLOUGHLIN,OF NEV YORK, N. Y.

AIR CUSHION FOR THE RECIPROCATING BEDS OF PRINTING-PRESSES.

SPECIFICATION forming part of Letters Patent No. 291,875, dated January15, 1884.

(No model.)

y citizen of the United States, residing at Brooklyn, Kings county, NewYork, have invented certain Improvements in Air Cushions for theReciprocating Beds of Printing-Presses, of which the following is aspecification. l

p My invention relates to air cushions for checking the momentum of thereciprocating beds vof printingpresses For this purpose fixed air-bellsor open-ended cylinders are commonly employed, fastened to the frame ofthe machine in connection with pistons mounted upon the reciprocatingbed, and entering the air-bells at each end of the stroke of the bed.These bells have been made adjustable by setting them bodily toward orfrom the bed by means of set-screws, in order to regulate the depth towhich the pistons on the bed shall enter them, and consequently theextent of resistance oi' the air cushion. But with the constructionsheretofore employed it has been practically impossible to cif'ect thisadjustment ofthe depth of the aircushions except when the machine was atrest, the cylinders or airbells being set to an approximately correctposition at first, and their effect then tried by running the press, andif they were found to give too deep or too shallow a cushion, the presswas stopped and they were set to a different position. Furthermore, thetwo airbells at opposite ends of the press have been unconnected witheach other, and it has been necessary to adjust them separately.

Inasmuch as printing-presses are operated at varyin g speeds, being runsometimes faster than at others, and as the momentum of the bed becomesgreater as the speed of the press increases, and as a deeper air cushionis necessary to overcome this momentum as the speed of the bed isincreased, it is highly desirable that the depth of the air cushionsshould be made quickly and easily adjustable to adapt the press todifferent speeds, and that this adjustment shall be made simultaneouslywith both air-bells and without stopping the press. To this end Iconnect both air-bells together in such manner that both shall approachtoward or recede from the middle of the press simultaneously, and lprovide mechanism for so moving them, capable of being operated: by theattendant of the press while the latter is running, so that as the speedof the press increases he can cause the air-bells to approach, and soproportionately' deepen the air cushions.

Another feature of 'my invention consists in constructing the aircushions by mounting a fixed piston on the machine exactly in line,axially, with the piston borne by the re*- ciprocating bed, and in sucha position that the latter piston will approach very near it when thebed reaches the end of its stroke, and arranging a cylinder or bell toembrace the xed piston, and to be slid along thereon to project more orless beyond the same, so that the capacity of the portion of thecylinder between its open mouth and the fixed piston inside may bevaried. Thus the capacity of t the bell is varied, and of course theamount of 7o air at the normal tension, which is compressed by themoving piston, may be also varied at will; but as the travel of themovingpiston does not vary, the tension of the air compressed willdepend upon its quantity.

In the accompanying drawings, Figure lis a plan view designed toillustrate my invention, and Fig. 2 is a vertical longitudinal sectiontaken in the axes of' the bells and pistons. Figs. 3, 4, and 5 are viewsdesigned to illustrate modifications, which will be hereinafterdescribed.

Let A represent the frame of' a printingmachine or press, and B thereciprocating bed, arranged to be reciprocated by any means S5 whatever.

On the frame A, at each end, are mounted, fixedly, two studs, C C', andon the ends of these studs are mounted, xedly, two pistons, D D. Mountedon the studs C C, so as to slide thereon, are two cylindrical bells, EE, in which the-fixed pistonsD D fit snugly. By moving the bells alongin the direction of their axes on the studs C C, the fixed pistons arebrought nearer to or farther from the open mouths of the bells, and thecapacity 'of-the bell is thus varied, as will be well understood.

Mounted on the bed B are two pistons, F F, the axes of which are alignedwith the axes of the bells, so that when the bed reaches the end ioo ofits stroke to the left, as shown in Fig. 2, the piston F will haveentered the bell E and compressed the air therein, when at the end ofits stroke the piston F stands close to and face to face with the iixedpiston D. If it be desired toincrease the tension of the compressed airin the bells, the latter are moved inward or toward each other, so as toincrease their capacity. If it be desired to decrease the tension, theyare moved outward or f'rom each other, so as to lessen their capacity.Of course the normal size of the cylindrical bell is not altered, vbutthe fixed piston inside of it serves as a sort of movable bottom orhead, which, although stationary, moves with respect to the cylinder orbell. 'Io shift both bells to the same extent and at the same time, anyone of several different kinds of mechanical Vdevices may be employed.That shown in Figs. 1 and 2 comprises two rods, a a', secured at theirouter ends to the bells E and E, respectively, and bearing on theirinner ends racks b b', which mesh with opposite sides of a pinion, c, ona cross-shaft, c', mounted rotatively in the main frame. By rotatingthis pinion, the bells may be moved out or in simultaneously, and toalike extent, and by securing the crank on shaft c, the bells will beretained in position. Fig. 3 shows a mechanism for the saine purpose inwhich each bell is provided with a rack on its under side with whichmeshes a pinion 4mounted rotatively in the frame A. To the outer ends ofthe shafts of these pinions are fixed oppositcly-arranged cranks d d',connected by a rod, e, which passes through and slides in aswivel-bearing, j', on frame A. By moving rod c endwise the pinions arerol tated and the bells moved in or out. The rod c may be secured in thebearing f by a setscrew, g, to hold the bells in place. Fig. 4. shows aysimilar' arrangement in which the cranks d d are replaced byworm-wheels, and the rod e by a shaft bearing right-andleft screws orworms, h 71.', which mesh with the worm-wheels. The shaft may be rotatedby a crank and will move the bells out or in, as desired. The screws 7L7L will serve as locks.

It will be obvious that if the bell be moved outward until the fixedpiston stands in its mouth,`there will be no compression of air, and themovement of the bed will not be checked; but if the bell be moved inwardas far as possible the compression will be very grat-about iiveatmospheres, in practiceand considerable heat will be generated. Thisheat will, by expansion, increase the tension, and I contemplateutilizing this extra tension to neutralize the friction of the movingpiston in the bell, which would otherwise have to be taken into accountin estimating the retarding force. I estimate this extra tension assufficient to overcome the friction of the piston when the latter iswithdrawn on the return-stroke. The tension exclusive of this-thatis,'the normal tension due to mechanical coinpression-f-scrves toovercome the 1 therewith.

inertia of the bed in starting. Before the press is started theair-bells should be moved inward with the fixed pistons standing at ornear their mouths, so that little or no cushoning will result. The pressis then started, and as its speed increases the attendant shouldgradually move the bells toward each other, thereby deepening the aircushions until the regular maximum speed of the press is attained, whenhe should carefully adjust the air cushions to such depth that the bedof the press will be caused to slow up and reverse its motion at eachend of its stroke with the utmost smoothness of movementy and absence ofvibration. In stopping or slowing up the press the air cushions shouldbe made shallower to a corresponding extent.

In Fig. 5 I have shown a modification, in which the fixed piston D isomitted and the bell E is fixed directly to a stem, C, arranged to slidein a bearing on the frame A. A rack,

b, is formed on the bottom of the bell and a worm, h, on a shaft, e,arranged to engage By this means the bells may be moved .in or out, ascircumstances may require. I have shown but one end of the device insection; but it will be understood that bothends arealike. ,In thisconstruction of bell, which is that heretofore used, the volume of aircompressed is always the same, and the tension due to compression isgoverned by the distance the piston enters into the bell. In my improvedconstruction of bell-first 4herein described, the tension is governed bythe volume of air compressed, which 1s capable of being varied by theshifting of the bell. Any number of air-bellsmay be provided. I usuallyemploy four, two at cach end of the frame.

Having thus described my invention, I Claimv l. As a means for checkingthe momentum of the reciprocating bed of a printing-press, thecombination, with said bed and pistons IOO IIO

borne thereby, of air-bells arranged at opposite ends of the machine,mounted upon the fixed frame thereof and adjustable axially toward andfrom eachl other, and mechanism, substantially as set forth, connectedwith said air-bells for moving them simultaneously toward or from eachother.

2. As a means for checking the momentum of the reciprocating bed of aprinting-press, the combination, with said bed and pistons bornethereby, of axially-movable air-bells arranged at opposite ends of themachine, where they will be entered by said pistons at the extremestroke of the bed, and mechanism, substantially as set forth, connectedwith said bells, the operation of which causes the bells to move towardor from each other simultaneously and to the same extent, and which iscapable of operation while the press is running, as described.

' 3. As a means for checking the momentum of the bed of aprinting-press, the combination,

with the bed, of a piston borne thereby, a bed and the pistons bornethereby, of the fixed fixed piston, and a movable bell adapted to bepistons, the movable bells, the rods a a', the shifted in the directionof its axis over said racks b b, and the pinion c, all arranged subi 5fixed piston, all arranged to operate substanstantially as set forth. 5tially as set forth. In witness whereof I have hereunto signed l. Thecombination, with the reciprocating my name in the presence of twosubscribing bed, the pistons F F borne thereby, the pis- Witnesses.

tons D D, :Xedly mounted on the frame, and T the movable bells E E, ofthe means, substan- A DREW CAMPBELL' Io tially as described, forshifting said bells si- Witnesses:

multaneously and equally, as set forth. G. M. HUDSON,

5. The combination, with the reciprocating HENRY MAGOWAN.

